CVE-2003-1031 in vBulletin
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in register.php for vBulletin 3.0 Beta 2 allows remote attackers to inject arbitrary HTML or web script via optional fields such as (1) "Interests-Hobbies", (2) "Biography", or (3) "Occupation."
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability described in CVE-2003-1031 represents a classic cross-site scripting flaw affecting vBulletin 3.0 Beta 2 software. This issue resides within the register.php script which processes user registration data and fails to properly sanitize input received through specific profile fields. The vulnerability specifically targets three optional user profile fields including "Interests-Hobbies", "Biography", and "Occupation" where user-supplied content is directly embedded into web pages without adequate validation or encoding mechanisms. This weakness allows remote attackers to inject malicious HTML or JavaScript code that executes in the context of other users' browsers when they view the affected profile information.
From a technical perspective this vulnerability maps directly to CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is embedded into web pages without proper validation or encoding. The flaw occurs because the vBulletin application does not implement proper input sanitization or output encoding for user-entered content in these specific profile fields. When users register or update their profiles with malicious payloads in these optional fields, the application stores the data verbatim and later renders it without escaping special characters that could be interpreted as HTML or JavaScript commands. This creates a persistent XSS vector where the malicious code becomes part of the web page content and executes in the browser context of other users who view the affected profiles.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with significant capabilities to compromise user sessions and access sensitive information. An attacker could craft malicious entries containing JavaScript code that steals cookies, session tokens, or other sensitive data from users browsing affected profiles. The vulnerability affects all users who view the compromised profile information, making it particularly dangerous in community forums where users frequently browse other members' profiles. Additionally, the persistent nature of stored XSS means that the malicious code remains active until the profile is updated or the content is removed, allowing attackers to maintain long-term access to victim systems. This type of vulnerability falls under ATT&CK technique T1531 which involves the use of malicious scripts to gain access to user sessions and data.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and output encoding mechanisms. System administrators should ensure that all user-supplied content in profile fields undergoes strict sanitization before being stored or rendered in web pages. This includes implementing HTML entity encoding for special characters and employing content security policies to prevent unauthorized script execution. The most effective remediation involves upgrading to a patched version of vBulletin that addresses this specific vulnerability, as the original software version contains fundamental flaws in its input handling mechanisms. Organizations should also consider implementing web application firewalls and monitoring for suspicious script injection patterns. Regular security audits of web applications should include comprehensive testing for XSS vulnerabilities in all user-input fields, particularly those that are optional or user-editable, to prevent similar issues from persisting in the application's codebase.